Damper construction and spring



United States atet [72] lnventor James R. Root Independence, Missouri [21] Appl. No. 729,995 [22] Filed May 17, 1968 [45] Patented Aug. 25, 1970 [73] Assignee Ruskin Manufacturing Company Kansas City, Missouri a corporation of Missouri [54] DAMPER CONSTRUCTION AND SPRING 9 Claims, 8 Drawing Figs.

[52] U.S.Cl 160/1, 160/207, 160/235 [51] Int. Cl E05d7/10, E06b3/ 32 [50] Field ofSearch 160/1,5,6, 199, 206, 207, 213, 183, 229, 235; 16/180- 190; 24/81C, 139, 139.1

[56] References Cited UNITED STATES PATENTS 251,591 12/1881 Jaeger 16/180 2,869,959 l/1959 Kesling 16/180(Y)UX 3,273,632 9/1966 Mc Cabe 160/1 3,327,764 6/1967 Mc Cabe 160/5 3,401,734 9/1968 Mc Cabe 160/207 885,008 4/1908 Beard 24/8 1 (C)UX 1,270,412 6/1918 Medrick... 24/81(C)UX 2,496,811 2/1950 Newton 24/8l(C)UX Primary Examiner Peter M. Caun Attorney- Don N. Bradley ABSTRACT: A folding blade damper comprising a rectangular frame and an assembly of blades hingedly interconnected along longitudinal marginal edges by tubular hinge elements. A torsion spring is interposed between each interconnected pair of blades to resiliently urge the blades from a folded to an unfolded, flow blocking position across the frame. The torsion spring comprises an initially straight wire component bent upon itself to present a pair of elongated torsion elements received in the tubular hinge, and integral hook structure on each element and secured to a respective blade to exert a torque between said blades.

Patented Au 25, 1910 Sheet all \ INVENTOR James R. Roof Patentd Aug. 25, 1970 3,525,378

R RINVENTOR :39 James 007* By I %%EYS.

DAMPER CONSTRUCTION AND SPRING This invention relates to closures, and more particularly to a folding blade closure such as a fire damper or the like.

Closures of this type conventionally comprise an assembly of hingedly interconnected blades which are normally disposed in a folded, stand-by position adjacent one side of a rigid, rectangular, peripherally extending frame. The unit may be interposed in an air duct or the like for closing the duct in the event ofa fire. In such case, the folded assembly is conventionally held in such stand-by position by a destructible device which may include a temperature fusible link. When the heat melts the link, the assembly is expected to automatically move to its flow blocking position.

When the frame can be mounted vertically across a generally horizontally extending duct or passage, gravity may often be relied upon for unfolding the blades of the assembly. When, however, the unit must be installed in a horizontal position as is necessary for protecting a vertical shaft, auxiliary --aprings are necessary for motivating the blade assembly across the frame opening upon destruction of the temperature sensilive device.

Dampers of this type are installed as safety precautionary measures, and must be capable of reliable performance even after long periods of inactivity. conventionally, tension springs are attached to the end blade of the assembly for pulling the closure across the frame upon melting of the fusible link. These tension springs may become fouled with corrosion or may otherwise become ineffective after long periods of inactivity. They may also create undesirable vibratory sounds when acted upon by the air stream flowing through the unit.

Accordingly, it is an important object of this invention to provide a unit having novel torsion springs carried by the blades of the closure and which are highly reliable when called upon for moving the blades to the flow blocking positions.

In the achievement of the foregoing object, it is another important object of this invention to provide springs which are relatively invulnerable to corrosion and which do not lose their effectiveness during relatively long periods of stand-by service.

Still another important object of the present invention is the provision of blade operating springs which occupy a minimum of space in the assembled unit and which do not interfere with or vibrate as a result of flow offluid through the open unit.

A yet further object of this invention is the provision of springs for the purpose described, which springs may be easily and economically made from commercially available materials and which may be quickly and easily installed in the assembly by relatively unskilled labor.

Another object of the invention is the provision of torsion springs which may be readily installed on any of a number of conventional fire damper units having a wide variety of blade configurations.

Yet a further object of the invention is the provision of a torsion spring for fire dampers or the like which torsion spring may be advantageously utilized in conjunction with conventional tension springs for insuring positive latching upon closing of the blade assembly of the damper.

These and other objects of this invention will be further explained or will become obvious from the following specification and claims and from the drawings.

In the drawings:

FIG. 1 is a fragmentary, vertical cross-sectional view through a fire damper illustrating the blade assembly in elevation and in its stand-by position;

FIG. 2 is a view similar to FIG. 1, but showing the blade assembly in its closed position;

FIG. 3 is an enlarged, fragmentary top plan view of a pair of interconnected blades and showing a spring installed in the hinge;

FIG. 4 is a side elevational view of the spring of FIG. 3;

FIG. 5 is a fragmentary, horizontal cross-sectional view taken along line 55 of FIG. 2;

FIG. 6 is a fragmentary, vertical cross-sectional view of a modified form of fire damper equipped with springs con structed pursuant to this invention, the blade assembly being shown in stand-by position;

FIG. 7 is a fragmentary view similar to FIG. 6 but showing the blade assembly in its closed position; and

FIG. 8 is a fragmentary, horizontal cross-sectional view taken along line 8-8 of FIG. 6.

Referring initially to FIGS. 1 and 2, a closure 10 in the nature of a fire damper is provided with a generally rectangular peripherally extending frame 12. Frame 12 is constructed from an initially flat band 14 of material such as sheet metal. The outermost marginal edge of band 14 is bent back upon itselfto present a rim 16 for frame 12. The end portion 18 of the edge margin of band 14 is then bent inwardly normal to the main plane of band 14 to present an integral stiffening rib for the frame.

A blade assembly 20 comprising a plurality of identical blades 22 is mounted within frame 12. Each blade 22 is provided with a relatively large, generally tubular hinge element 24 on one marginal edge thereof and a somewhat smaller generally tubular hinge element 26 in the opposite marginal edge thereof. The hinge element 26 of one blade 22 is partially telescoped within the hinge element 24 of the next adjacent blade 22 to provide a tubular hinge 28 between each pair of adjacent blades 22 of the assembly 20. Mounting means in the nature of a blade 30 having its hinge element 24 removed is rigidly secured along one side of frame 12 and extends downwardly at an angle as illustrated in FIGS. 1 and 2. The hinge element 24 of the uppermost blade 22 of assembly 20 is hingedly secured to blade 30 to permit articulation of each of the blades 22 as will be hereinafter described.

Referring now to FIG. 1, it may be seen that the longitudinally extending blades 22 may be reversely folded upon one another to positions generally as illustrated in FIG. 1 wherein the assembly 20 is compactly positioned adjacent one side of frame 12. Manifestly, relatively uninhibited flow of fluid is thereby permitted through frame 12. It is contemplated that frame 12 will be installed in a duct or ventilation shaft or the like.

Referring now to FIGS. 3 and 4 in conjunction with FIGS. 1 and 2, a torsion spring 32 is provided between the respective blades 22 for urging the blades from the folded position thereof as illustrated in FIG. 1 to the unfolded position as illustrated in FIG. 2. Each torsion spring 32 may be constructed from an initially straight wire component bent to present a pair of elongated, parallel, transversely circular stretches 34 adapted to be received within the tubular hinges 28 with the integral bight 36 which interconnects stretches 34 being disposed in longitudinally spaced relationship along stretches 34 from the end edges 38 of the respective blades 22 interconnected by the hinge 28. The stretches 34 comprise torsion elements which extend generally axially of the hinge 28 and are bent adjacent edges 38 to present hooks 40. It will be noted that each hook 40 extends laterally from the longitudinal axis of its stretch 34 and is engaged with the proximal blade 22 along edge 38 to releasably secure the torsion element to its respective blade 22. Thus, the hooks 40 of the two respective stretches 34 of each spring 32 extend in opposite directions and serve to bias the respective blades of a hinged together pair thereof into the unfolded position as illustrated partially in FIG. 3 and in particular in FIG. 1. It should be noted that bushing 42 which may be in the nature of a commonly available grommet having a cylindrical portion 44 and an integral flange 46 is telescoped over stretches 34 and engages the end edges 38 of hinge 28 of the respective blades. Thus, bushing 42 serves to center the stretches 34 in the hinge. This prevents any tendency for binding of the wire component of spring 32 during articulation of the hinge joint and insures freedom of movement at all times.

The blade assembly 20 provided with springs 32 in the respective joints 28 may be held in the folded position by a conventional temperature sensitive device such a circumscribing band 48 having temperature fusible link 50 interposed therein. It is contemplated that a spring 32 will be provided for each end of each hinge joint 28 to balance the forces tending to swing the blades to the unfolded position and to avoid any possibility of binding. It will be obvious, however, to those skilled in the art that it is not absolutely necessary that each of the hinge joints be provided with a spring 32. Rather, only sufficient hinge joints may be utilized as is necessary to impart a thrust to the blades capable of shifting the same to the unfolded position. When the fire damper is to be installed in a horizontal position, more spring energy will be required for closing the blade assembly than is necessary when the damper is installed in a vertical position and wherein gravity may be relied upon for moving the blades.

It is believed obvious from the previous description that the folding of the blades as illustrated in FIG. 1 results in a corresponding twisting of the elongated torsion elements 34. The hooks 40 assume positions generally as illustrated in FIG. 1 wherein one hook 40 moves to the outside of the other hook 40 of a spring 32 during the twisting of the torsion stretches 34. This accounts for the extension of one hook 40 further from the axis of a hinge joint 28 than the other hook 40 as is apparent in FIG. 1.

The energy stored in the twisted torsion elements or stretches 34 is released upon the separation of link 50 and the springs immediately unfold the blades. The closure panel provided by the articulated blade assembly 22 springs across the opening within the confines of frame 12. The inwardly projecting portions or ribs 18 on each side of frame 12 provide a channel 52 therebetween to guide the blades in the unfolding movement. A bracket 54 secured on a pair of sides of frame 12 adjacent the end thereof remote from blade 30 includes an upwardly extending hook portion 56 and a downwardly inclined ramp portion 58 angled in the direction of hook portion 56. The lowermost hinge element 26 of the end blade 22 contacts ramp 58 and the hinge element 26 slides along the ramp to the position illustrated in FIG. 2. This position brings the proximal face of the end blade 22 into engagement with hook portion 56 and prevents opening of the closure provided by the unfolded assembly 20. Manifestly, the proximal spring 32 has a tendency to bias the lowermost blade 22 into an angled position with respect to the next adjacent blade 22 rather than to a position where the blades are aligned so that any upward movement of the lower blade 22 will cause hinge element 26 thereof to engage hook portion 56.

Referring now particularly to FIGS. 6, 7 and 8, a modified form of closure is illustrated. Thus, a fire damper 110 is provided with a blade assembly 120 which may be made up of blades 122 in a manner identical to the description with respect to closure 10. In this case, however, auxiliary tension springs are provided for moving assembly 120 from its folded to its unfolded position. Spring 111 may be of conventional construction as is commonly used in the construction of conventional fire dampers and includes an elongated element 113 having the capability of exerting a constant tension on the blades irrespective of the extension of element 113. Element 113 coils itself about a spindle 115 during the unfolding of assembly 120.

conventionally tension springs 111 are mounted with the spindle 115 extending generally parallel to the longitudinal axis of hinging of the blades so that the forces imparted by spring 111 pull directly downwardly on the blades and toward a locking device or latch. This has the disadvantage, however, of turning the broad face of the relatively flat, tape-like element 113 transversely of the path of flow of fluid through the fire damper. This not only exposes the tension element 113 to a build up of corrosive substances which may have a deleterious effect upon operation of the fire damper, but also results in undesirable vibration of the elements 113 caused by action of the fluid current flowing through the damper.

It should be noted that the installation shown in FIGS. 6, 7 and 8 permits the element 113 to be disposed with its broad face generally parallel with the fluid stream and also positioned well to the side of the frame 112. It may be seen particularly in FIG, 8 that the pair of springs 111 offer very little fluid resistance to the opening through damper 110.

To accommodate for the mounting of the springs 111 as shown in FIGS. 68, the lowermost blade 122 of assembly 120 is provided with an elongated L-shaped bracket 117 for each spring 111. The short leg of each bracket 117 is rigidly secured to end blade 122 while the long leg of bracket 117 is pivotally coupled to the outermost end of spring element 113. Additionally, spindle is substantially longer than the width of element 113 so that the flanges 119 at each end of spindle 115 are spaced relatively far apart. This permits the angling of element 113 as illustrated in FIG. 6 without interference from the end flanges of spindle 115.

Upon unfolding of the assembly 120, the outer periphery of the coiled spring element 113 is sufficiently large that bracket 117 clears the adjacent flange 119 to permit movement of end blade 122 into the position illustrated in FIG. 7. Note that bracket 117 extends almost perpendicular from the longitudinal axis of the coiled spring element 113 in this position.

The utilization of the springs lll interferes with the provision of a ramp to guide the end blade 122 into engaged position with a hook 156 mounted on the frame 112. Accordingly, a spring 132 is utilized in conjunction with the lowermost hinge 128 of assembly 120. Spring 132 serves to bias the lower blade 122 toward hook 156 to securely latch the assembly in its unfolded fluid blocking position, It should be pointed out that the spring 122 may be configured to exert the biasing torque necessary for overcoming the tension of spring 111 to effect this latching function. Actually, when assembly 120 is unfolded, spring element 113 is substantially completely wound on spindle 115 and spring 132 merely needs to shift the coiled element 113 adjacent the flange 119 proximal hook 156. The extension afforded by bracket 117 brings the lowermost hinge element 126 into position to engage hook 156 should assembly 120 tend to move from its closed position.

I claim:

1. In a closure comprising a plurality of elongated blades, each blade being hingedly connected along a marginal edge to the adjacent blade for swinging movement between a folded position lying generally along said adjacent blade, to an unfolded position disposed generally in extension of said adjacent blade, spring means for urging a pair of said blades into said unfolded position, said spring means comprising:

a pair of elongated torsion elements disposed generally parrallel to the axis of swinging movement between said pair of blades;

arm structure for each torsion element respectively, each arm structure normally extending in the opposite direction from the other arm structure, with each structure being secured to its corresponding blade of said pair thereof in radially spaced relationship from said axis of swinging movement; and

means rigidly interconnecting the torsion elements in longitudinally spaced relationship from each of said arm structures, whereby the twisting of said torsion bars upon folding of said pair of blades biases said arm structures in directions to return said blades to said unfolded position.

2. Apparatus as set forth in claim 1, wherein said blades are interconnected by a tubular hinge, and wherein said torsion elements are received in said tubular hinge.

3. Apparatus as claimed in claim 2, wherein each structure is provided with a hook, each hook being engaged over an end edge of a corresponding blade.

4. Apparatus as claimed in claim 2, wherein said elements are integrally interconnected in longitudinally spaced relationship along the elements from said hooks.

5. Apparatus as claimed in claim 1 wherein is provided a spring means for each end of said hinge.

6. A closure comprising, in combination:

a rigid rectangular frame, including spaced apart frame side members;

a plurality of elongated blades, said blades extending tubular hinge means carried by adjacent marginal edges of said blades for interconnecting each blade with an adjacent blade for folding of said interconnected pair of blades along the axes of said hinge means; and

torsion spring means for each hinge means respectively,

each spring means including an initially straight wire component bent upon itself to present a pair of elongated stretches extending into said tubular hinge from one end thereof, a hook formed on the outermost end of each stretch respectively, each hook being engaged over a corresponding one of said blades, the ends of said stretches being connected together and the hooks of said interconnected pair of stretches normally extending in opposite directions to bias said blades toward an unfolded condition, whereby the folding of said blades twists said stretches to produce a force in the spring means for urging the blades toward said unfolded condition.

7. A closure panel as claimed in claim 6, wherein said frame includes a peripherally extending, initially flat band of sheet material, the outermost edge margin of said band being bent back upon itself to present a rim for said frame, the end portion of said edge margin being bent inwardly normal to said rim to present an integral stiffening rib for said frame.

8. A closure comprising, in combination:

a rigid, rectangular frame;

an assembly of elongated blades;

hinge means carried by marginal edges of said blades for interconnecting each blade with an adjacent blade for swinging of said blades about said hinge means from folded positions adjacent one side of said frame to unfolded positions blocking flow of fluid through the frame;

means securing one of said blades to said one side of the frame, the end blade remote from said one blade having an outermost edge formed to present a hook;

tension spring means mounted on the side of said frame opposite said one side thereof, said tension spring means being secured to said end blade;

a catch carried by the frame in disposition to engage the hook of said end blade for releasably latching said assembly in said unfolded position, said hinge means interconnecting the end blade with the adjacent blade being tubular; and

torsion spring means interposed between the end blade and said next adjacent blade for exerting a torque on said end pair of blades to bias the book of the end blade toward said catch.

9. A closure as claimed in claim 8, whereby said end blade is provided with a rigid bracket projecting from one surface thereof, said tension spring means being secured to the bracket in spaced relationship from said surface of the end blade. 

